This invention relates to the handling of organic solid waste materials and more particularly to the converting of the combustible fraction of organic solid waste materials to a useable fuel material.
The disposal of organic solid wastes has become an increasingly severe problem in view of the increasing population, the concentration of populations in urban and suburban areas and the increasing number of industries generating organic solid wastes. A large fraction of such organic waste is combustible and is made up of such materials as paper, textiles, leather, rubber, yard wastes, wood, wood wastes and bark, garbage and some forms of plastics. The process of this invention is directed to the conversion of this combustible fraction of solid organic wastes into a finely divided product which can be used as a fuel or fuel supplement.
Inasmuch as it is becoming increasingly difficult to dispose of solid wastes by such previously used means as dumping and filling, a critical need has arisen to find other techniques for solid waste disposal, such techniques of necessity being those which do not create pollution problems and of preference those which do not require the expenditure of appreciable amounts of energy. Moreover, if the end product or products of the disposal process are themselves usable, the process is even more desirable.
In general, the processes more recently proposed for solid waste disposal may be classed as bulk reduction, conversion or reclamation. Although some advances in bulk reduction (densification) have been made, each of the techniques used (baling, incineration, etc.) have inherent drawbacks including disposal of the densified material, pollution control, and the like. Conversion is generally defined as the chemical or biochemical transformation of the waste material into a useful product; and the techniques used include pyrolysis (destructive distillation or decomposition at elevated temperatures, e.g., 750.degree.-1600.degree. F in the absence of air or other reactive or oxidizing gases), composting (aerobic conversion of cellulose waste into inert humus-like material by aerobic bacteria), hydrogenation, wet oxidation, hydrolysis, anaerobic digestion, biological fractionation and the like.
Reclamation involves the separating out from the solid waste of such materials as glass, plastics, metals, papers, textiles and the like for reuse in one form or another. However, other than some forms of papers, plastics and textiles, the combustible component of organic solid wastes which have caloric value have not been recovered. Only recently has any serious attempt been made to convert these combustible material to a form in which they could be used as a fuel.
By the process of this invention it is possible to treat the combustible fraction of organic solid wastes to form a finely divided, relatively dense fuel or fuel supplement using a relatively small amount of energy and employing known apparatus components. The resulting product is a finely divided material usable as a fuel or fuel supplement in existing combustion equipment without requiring any substantial modification. This product retains essentially all of the dry weight and caloric content of the original solid organic waste material from which it is formed.
It is therefore a primary object of this invention to provide a process for treating the combustible fraction of solid organic wastes, the processing comprising the embrittlement of the solid organic wastes, to form it into a fuel or fuel supplement. It is another object to provide a process of the character described which can be carried out with the expenditure of relatively little energy so that the net result of the process is an energy gain in the form of caloric fuel.
A further object is to provide a process for destroying any fibrous characteristics of the solid organic waste to increase its bulk density and improve its handling characteristics. Still another object of this invention is the providing of such a process which does not involve substantial pyrolysis, decomposition, or chemical conversion and therefore does not generate pollution control problems. It is a further object of this invention to provide a process of the character described which can be carried out in available apparatus components and which can be readily adapted to conditions prevailing within a given area to form a fuel product best suited for the area in which it is produced or to be used.
It is another primary object of this invention to facilitate the separation of the organic and inorganic constituents of solid waste by selective embrittlement of the organic fraction.
It is yet another primary object of this invention to provide a unique fuel or fuel supplement formed from the combustible fraction of solid organic wastes. It is a further object to provide a fuel of the character described which retains essentially all of the dry weight and caloric value, in a greatly densified form, of the organic material from which it was formed. It is yet another object to provide such a fuel or fuel supplement which may be stored and handled without undergoing decomposition. An additional object is to provide a fuel of the character described which may be pelletized or compacted under pressure. It is a further object to provide a fuel supplement suitable for mixing with gaseous, liquid or solid hydrocarbon fuels either prior to or during combustion.
Other objects of the invention will in part be obvious and will in part be apparent hereinafter.